Background: Current literature reports that the traditional methods overestimate renal function in spinal cord injury (SCI); however, there is no accepted standard method. Objective: This study evaluated 6 published methods against measured aminoglycoside (AG) drug clearance and determined the frequency with which each method would achieve target peak and trough AG concentrations within a specified range. Methods: A chart-based investigation was conducted at a hospital with a large SCI population, and a total of 35 patients met the inclusion criteria: a diagnosis of long-standing SCI, administration of AG via intravenous infusion, and at least one set of steady-state AG peak and trough concentrations. Pharmacokinetic analysis was performed to compare the measured AG clearance values against the values resulting from 6 methods of estimating the glomerular filtration rate (GFR). Patient-specific pharmacokinetic parameters were used to simulate steady-state peak and trough AG concentrations from doses derived from each method. Results: Compared with the other methods, the Lee-Dang method was found to be more accurate, with the smallest magnitude of variance from the measured AG clearance values. Five alternative methods significantly overestimated AG clearance, by approximately 70% to 160% (P < .05). The Lee-Dang method underestimated AG clearance (by 10%), however not to a significant degree (P = .079). Compared with the alternative methods, the Lee-Dang method resulted in a higher frequency of steady-state peak and trough AG concentrations within the target range specified. Conclusion: The Lee-Dang equation for predicting GFR was more accurate relative to the other methods in the study population of patients with long-term SCI.